Diesel particulate filters (DPF) are required on many modern diesel powered vehicles. During the trapping mode of operation, increasing soot loading in the DPF creates back pressure on the engine, thereby degrading fuel economy and engine performance with a potential of engine damage. High temperatures during regeneration can lead to DPF failures, such as cracking, resulting in leakage of particulates. Original Equipment Manufacturers (OEMs) are required by the Environmental Protection Agency (EPA) to certify with on-board diagnostics (OBD) that their diesel emissions control system is functioning normally and the emissions of particulate matter (PM) are below a certification limit (0.01 g/hp-hr), and to detect loss of performance before the actual emissions of PM exceed the threshold (0.05 g/hp-hr) (for all engine families starting in 2013, and for one engine family starting 2010). Today, the best available solution is to monitor the engine operation and the pressure drop across the DPF as well as the DPF regeneration control system with software within the engine control unit to detect loading of the DPF as well as problems with the equipment. However, the current best approach does not directly or accurately measure DPF loading or performance and thus cannot insure compliance.